Circuit arrangement for changing two electrical analog quantities



June 20, 1967 w. GUGGENBUHL 7 3,327,231

CIRCUIT ARRANGEMENT FOR CHANGING TWO ELECTRICAL ANALOG QUANTITIES Filed Sept. 5, 1964 2 Sheets-Sheet l x} J I: o. d. (55

2 x x Y) P l g Z v W f mf mlz) June 20, 1967 w. GUGGENBUHL 3,327,231

CIRCUIT ARRANGEMENT FOR CHANGING TWO ELECTRICAL ANALOG QUANTITIES Filed Sept. 5, 1964 2 Sheets-Sheet 2 x 3 IE 5" i f w I; N 0: m .2 m m cm I O m K United States Patent 3,327,231 CIRCUIT ARRANGEMENT FOR CHANGING TWO ELECTRICAL ANALOG QUANTITIES Walter Guggenbiihl, Zurich, Switzerland, assignor to Contraves Ag., Zurich, Switzerland Filed Sept. 3, 1964, Ser. No. 394,365 Claims priority, application Switzerland, Sept. 3, 1963, 10,851/ 63 8 Claims. (Cl. 329-167) ABSTRACT OF THE DISCLOSURE An arrangement for modifying two analog voltages, particularly if they are vector components. The modification to the analog quantity is in the form of applying an identical factor to both electrical voltages representing the analog quantities. The result produced by the arrangement is that both analog quantities are multiplied by one and the same factor.

The present invention concerns a circuit arrangement for processing analog information, and more specifically for changing two electrical analog quantities by applying a factor to both quantities. It is well established in the art that analog electrical: quantities are the result of measuring a physical quantity as for instance pressure, temperature, humidity, speed of movement etc. in contrast to digital values which are the result of a counting operation. A good definition of the term analog information is given on page 287 of Understanding Digital Computers by Paul Siegel, published 1961 by John Wiley & Sons, Inc., New York.

By way of example a circuit arrangement of the type set forth is useful for limiting or otherwise influencing and changing two analog quantities which may be the Cartesian components of a vectorial quantity. In such cases it is frequently of great importance that both components are changed by the same factor applied to both components in order that the resulting direction of the vectorial value be kept unchanged. However, it is extremely difficult to change two electrical quantities in accordance with an identical program applying to both if the device which produces the change of magnitude or of another characteristic of the electrical quantities is a variable resistor or another type of transducer which is controlled photo-electrically, thermo-electrically or magneto-electrically and has an output characteristic which is difficult to keep or make a linear characteristic.

It is therefore one object of this invention to provide for a circuit arrangement which overcomes the above-described difficulties.

It is another object of this invention to provide for a circuit arrangement as set forth which is comparatively simple in its structure and entirely reliable and efiicient in operation.

With the above objects in view the invention includes a circuit arrangement for simultantouslyand concurrently changing two electrical analog quantities by applying a factor to both quantities, comprising, in combination, first and second input means for introducing, respectively, a first and a second analog direct current voltage, generator means for producing a first rectangular alternating voltage of a predetermined frequency and for producing a second rectangular alternating voltage of substantially identical frequency but phase-shifted 90 with respect to said first alternating voltage, first modulator means connected with the generator means andwith the first input means for modulating the first analog voltage with the first rectangular voltage, second modulator means connected with the generator means and with the second input means for modulating the second analog volttage with the second rectangular voltage, adding stage means connected with both the modulator means for adding the modulated output voltage thereof and for furnishing a combined output voltage representing the sum of the two modulated output voltages, multiplying means connected with the output of the adding stage means for changing the valve of the combined output voltage, and demodulator means connected with the output of the multiplying means for demodulating the combined output voltage as changed by the multiplying means, the demodulating means being connected with the generator means for being synchronized by the first and second rectangular alternating voltages in such a manner that the demodulator means deliver a first and a second final output voltage corresponding, respectively, to the first and second analog voltage, both the analog voltages appearing in the final output voltages as being changed identically in accordance with the change applied to the combined output voltage by the multiplying means.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which:

FIG. 1 is a schematic circuit diagram of a circuit arrangement according to the invention; and

FIG. 2 is a schematic circuit diagram illustrating more specifically an example for a generator forming part of the arrangement according to FIG. 1.

As can be seen from FIG. 1, the circuit arrangement illustrated thereby comprises first of all two sources of a direct current voltage or more specifically two generators of the like G and G which are controllable individually by relatively slowly varying physical quantities so as toproduce two analog direct current voltages U and U,,, respectively. Thus the generators or sources G and G are the input means for the introduction of a first and a second analog direct current voltage.

The analog voltages U and U are introduced into substantially identical modulator stages M and M respectively, which are preferably constructed as conventional passive chopper oscillator circuits comprising each at least one switching or control transistor Tm and T m respectively.

A generator or other source Q of two rectangular alternating voltages U and U respectively, is connected, as shown with the modulator stages M and M so as to apply the two rectangular alternating voltages to the base electrodes of the transistors T and T respectively. The rectangular alternating voltages U and U,,, have substantially the same frequency but the phase of the voltage with the frequency i is shifted relative to the other voltage having the frequency fswz) by 1r/2 or 90 as illustrated in FIG. 1. A preferred embodiment of a generator Q will be described further below in reference to FIG. 2. I I

By the application of the rectangular alternating voltages U and U to the modulator stages M and M respectively, the analog input voltages U and U respectively, are modulated with the frequency f of the output of the generator Q with the result that the modulator stages M and M deliver modulated analog voltages U and U,,*, respectively, as indicated in FIG. 1.

These modulated analog voltages are introduced jointly,

' into a conventional adding stage I -comprising a tranducer P constituted e;g. by a photo-electrically controlled variable resistor or potentiometer. In accordance with any desired program or with the control exerted 'on the variable resistor P (or any other type of a transducer) the combined output voltage of the adding stage I, representing the sum of the above-mentioned two modulated output voltages of the modulators, namely the combined output voltage S* is changed or modified so that the output of the multiplying stage is accordingly changed combined output voltage as indicated, namely pS* This changed combined output voltage is preferably amplified by an amplifier V and thereafter introduced into two demodulator stages D and D respectively. These demodulator stages are constructed substantially identical with the above-described modulator stages M and M and comprise also at least one control transistor Td and Td respectively, and additionally, a conventional RC-filter at the output thereof. The control transistors Td and Td are controlled for the purpose of synchronization also by the above-mentioned rectangular alternating voltages U and U respectively, furnished by the generator Q In this manner, the changed combined output voltages introduced into the two demodulator stages D and D are demodulated in a well known manner so that at the two outputs of the demodulator stages D and D -the desired changed analog direct current voltages pU and pU respectively, are delivered which correspond exactly to the input voltages U and U but both being changed substantially identically in response to the action of the multiplying means described above.

Referring now to FIG. 2, the generator Q may comprise, first of all, a conventional multi-vibrator MV constructed so as to produce a primary rectangular alternating voltage having a primary frequency four times said predetermined frequency i of the desired rectangular output voltage of the, generator. A portion of FIG. 2 illustrates, underneath the illustration of the multivibrator MV, 2. sequence of cycles of the primary frequency 41;. The output of the multivibrator MV having the abovementioned frequency 4 is applied to a first binary frequency divider stage BS of conventional type. The two outputs of this first frequency divider stage are two secondary rectangular alternating voltages having one half the frequency of the input voltage, namely a frequency 2f however, one of these output frequencies or secondary alternating rectangular voltages furnished by the frequency divider BS is inverted relative to the other, or which amounts to the same effect, phase-shifted 180 relative to the other one which is also illustrated in FIG. '2 below the illustration of the primary rectangular alternating voltage. Now, the two secondary rectangular alternating voltages with the frequency Zf are applied separately to a first and a second binary output frequency divider B5 and B8 respectively, as shown in FIG. 2. These frequency dividers are also of conventional type and similar to the first frequency divider BS so that, in view of means for phase-shifting included in at least one of these second frequency dividers, the outputs of the frequency dividers B8 and B5 furnish the desired modulating rectangular voltages U and U respectively, which are also illustrated in FIG. 2 as a diagram and which are the modulating voltages referred to in the description of FIG. 1.

It will be understood that each of the elements described above, or two or more together, may alsofind a useful application in other types of a circuit arrangement for simultaneously and concurrently changing two electrical analog quantities, differing from the types described above.

What is claimed as new and Letters Patent is:

1. A circuit arrangement for simultaneously and concurrently changing'two electrical analog quantities by applying a factor to both quantities comprising, in combidesired to be secured by nation, first andsecond input means for introducing, re-

spectively, a first and a second analog direct current volt-' means comprising multivibrator means for producing a primary rectangular alternating voltage of a primary frequency, a binary frequency divider means, for converting said primary frequency alternating voltage into two secondary rectangular alternating voltages phase-shifted 180- relative to each other, and a first binary output frequency divider means forconverting one of said secondary alternating voltages into said first rectangular alternating voltage of said predetermined frequency, and a second binary output frequency divider means for converting the other one of said secondary alternating voltages into said second rectangular alternating voltage; first modulator means connected with said generator means and with said first input means for modulating said first analog voltage with said first rectangular voltage; second modulator means connected withsaid generator means and with said secnishing a combined output voltage representing the sum.

of said two modulated output voltages; multiplying means connected with the output of said adding stage means for changing the value of said combined output voltage; and

demodulator means connected with the output of said multiplying means for demodulating said combined output voltage as changed by said multiplying means, said demodulating meansbeing connected with said generator means for being synchronized by said first and second rectangular alternating voltages in such a manner that said demodulator means deliver a first and a second final output voltage corresponding, respectively, to said first and second analog voltage, both said analog voltages appearing in said final output voltages as being changed identically in accordance wtihthe change applied to said combined output voltage by said multiplying means.

2. A circuit arrangement for simultaneouslyand concurrently changing two electrical analog quantities by applying a factor to both quantities comprising, in combination, first and second input means for introducing, respectively, a first and a second analog direct current voltage; generator means for producing a first-rectangular alternating voltage of a predetermined frequency and for producing a second rectangular alternating voltage of substantially identical frequency but phase-shifted 90 with respect to said first alternating voltage, said generator means comprising multivibrator means for producing a primary rectangular alternating voltage of aprirnary frequency four times said predetermined frequency, a binary frequency divider means for converting said primary frequency alternating voltage into two secondary rectangular alternating voltages of one-half the frequency of said primary alternating voltage, said two secondary alternating voltages being 1'80- phase-shifted relative to each other, and a first binary output frequency dividermeans for converting one of said secondary alternating voltages into said first rectangular alternating voltage of said predetermined frequency, and a second binary output frequency divider means for converting the other one of said secondary alternating voltages with a phase-shift into said second rectangular alternating voltage; first modulator means connected with said generator means and with said first input means for modulating said first analog voltage with said first rectangular voltage; second modulator means connected with said generator means and with said second input means for modulating said second analog voltage with said second rectangular voltage; adding stage means connected with both said modulator means for adding the modulated output voltages thereof and for furnishing a combined output voltage representing the sum of said two modulated output voltages; multiplying means connected with the output of said adding stage means for changing the value of said combined output voltage; and demodulator means connected with the output of said multiplying means by demodulating said combined output voltage as changed by said multiplying means, said demodulating means being connected with said generator means for being synchronized by said first and second rectangular alternating voltages, in such a manner that said demodulator means deliver a first and a second final output voltage corresponding, respectively, to said first and second analog voltage, both said analog voltages appearing in said final output voltages as being changed identically in accordance with the change applied to said combined output Voltage by said multiplying means.

3. A circuit arrangement for simultaneously and concurrently changing two electrical analog quantities by applying a factor to both quantities; comprising, in combination, first and second input means for introducing, respectively, a first and a second analog direct current Voltage; generator means for producing a first rectangular alternating voltage of a predetermined frequency and for producing a second rectangular alternating voltage of substantially identical frequency but phase-shifted 90 with respect to said first alternating voltage; first modulator means connected with said generator means and with said first input means for modulating said first analog voltage with said first rectangular voltage, said modulator means comprising a chopper oscillator circuit including at least one control transistor; second modulator means connected with said generator means and with said second input means for modulating said second analog voltage with said second rectangular voltage, said modulator means comprising a chopper oscillator circuit including at least one control transistor; adding stage means connected with both said modulator means for adding the modulated output voltages thereof and for furnishing a combined output voltage representing the sum of said two modulated output voltages; multiplying means connected with the output of said adding stage means for changing the value of said combined output voltage; and demodulator means connected with the output of said multiplying means for de modulating said combined output voltage as changed by said multiplying means, said demodulating means comprising a first and a second chopper oscillator circuit, each including at least one control transistor and an output filter circuit in series therewith, said first and second chopper oscillator circuits being connected with said generator means for being synchronized by said first and sec ond rectangular alternating voltages, respectively, in such a manner that said demodulator means deliver a first and a second final output voltage corresponding, respectively, to said first and second analog volt-age, both said analog voltages appearing in said final output voltages being changed identically in accordance with the change applied to said combined output voltage by said multiplying means.

4. A circuit arrangement for simultaneously and concurrently changing two electrical analog quantities by applying a factor to both quantities, comprising, in combination, first and second input means for introducing, respectively, a first and a second analog direct current voltage; generator means for producing a first rectangular alternating voltage of a predetermined frequency and for producing a second rectangular alternating voltage of substantially identical frequency but phase-shifted 90 with respect to said first alternating voltage, said generator means comprising multivibrator means for producing a primary rectangular alternating voltage of a primary frequency four times said predetermined frequency, a binary frequency divider means for converting said primary frequency alternating voltage into two secondary rectangular alternating voltages of one-half the frequency of said primary alternating voltage, said two secondary alternating voltages being 180 phase-shifted relative to each other, and a first binary output frequency divider means for converting one of said secondary alternating voltages into said first rectangular alternating voltage of said predetermined frequency, and a second binary output frequency divider means for converting the other one of said secondary alternating voltages with a phase shift into said second rectangular alternating voltage; first modulator means connected with said generator means and with said first input means for modulating said first analog voltage with said first rectangular voltage, said modulator means comprising a chopper oscillator circuit including at least one control transistor; second modulator means connected with said generator means and with said second input means for modulating said second analog voltage with said second rectangular voltage, said modulator means comprising a chopper oscillator circuit including at least one control transistor; adding stage means connected with both said modulator means for adding the modulated output voltages thereof and for furnishing a combined output voltage representing the sum of said two modulated output voltages; multiplying means connected with the output of said adding stage means for changing the value of said combined output voltage; and demodulator means connected with the output of said multiplying means for demodulating said combined output voltage as changed by said multiplying means, said demodulating means comprising a first and a second chopper oscillator circuit, each including at least one control transistor and an output filter circuit in series therewith, said first and second chopper oscillator circuits being connected with said generator means for being synchronized by said first and second rectangular alternating voltages, respectively, in such a manner that said demodulator means deliver a first and a second final output voltage corresponding, respectively, to said first and second analog voltage, both said analog voltages appearing in said final output voltages as being changed identically in accordance with the changed applied to said combined output voltage by said multiplying means.

5. A circuit arrangement according to claim 1, wherein said multiplying means comprise a variable resistance means connected between said output of said adding stage means and the input of said demodulating means for varying the amplitude of said combined output voltage.

6. A circuit arrangement according to claim 2, Wherein said multiplying means comprise a variable resistance means connected between said output of said adding stage means and the input of said demodulating means for varying the amplitude of said combined output voltage.

7. A circulit arrangement according to claim 3, wherein said multiplying means comprise a variable resistor means connected between said output of said adding stage means and the input of said demodulating means for varying the amplitude of said combined output voltage.

8. A circuit arrangement according to claim 4, wherein said multiplying means comprises a variable resistor means connected between said output of said adding stage means and the input of said demodulating means for varying the amplitude of said combined output voltage.

References Cited UNITED STATES PATENTS ROY LAKE, Primary Examiner.

ALFRED L. BRODY, Examiner. 

1. A CIRCUIT ARRANGEMENT FOR SIMULTANEOUSLY AND CONCURRENTLY CHANGING TWO ELECTRICAL ANALOG QUANTITIES BY APPLYING A FACTOR TO BOTH QUANTITIES COMPRISING, IN COMBINATION, FIRST AND SECOND INPUT MEANS FOR INTRODUCING, RESPECTIVELY, A FIRST AND SECOND ANALOG DIRECT CURRENT VOLTAGE; GENERATOR MEANS FOR PRODUCING A FIRST RECTANGULAR ALTERNATING VOLTAGE OF A PREDETERMINED FREQUENCY AND FOR PRODUCING A SECOND RECTANGULAR ALTERNATING VOLTAGE OF SUBSTANTIALLY INDENTICAL FREQUENCY BUT PHASE-SHIFTED 90* WITH RESPECT TO SAID FIRST ALTERNATING VOLTAGE, SAID GENERATOR MEANS COMPRISING MULTIVIBRATOR MEANS FOR PRODUCING A PRIMARY RECTANGULAR ALTERNATING VOLTAGE OF A PRIMARY FREQUENCY, A BINARY FREQUENCY DIVIDER MEANS FOR CONVERTING SAID PRIMARY FREQUENCY ALTERNATING VOLTAGE INTO TWO SECONDARY RECTANGULAR ALTERNATING VOLTAGES PHASE-SHIFTED 180* RELATIVE TO EACH OTHER, AND A FIRST BINARY OUTPUT FREQUENCY DIVIDER MEANS FOR CONVERTING ONE OF SAID SECONDARDY ALTERNATING VOLATAGES INTO SAID FIRST RETANGULAR ALTERNATING VOLTAGE OF SAID PREDETERMINED FREQUENCY, AND A SECOND BINARY OUTPUT FREQUENCY DIVIDER MEANS FOR CONVERTING THE OTHER ONE OF SAID SECONDARY ALTERNATING VOLTAGES INTO SAID SECOND RECTANGULAR ALTERNATING VOLTAGE; FIRST MODULATOR MEANS CONNNECTED WITH SAID GENERATOR MEANS AND WITH SAID FIRST INPUT MEANS FOR MODULATING SAID FIRST ANALOG VOLTAGE WITH SAID FIRST RECTANGULAR VOLTAGE; SECOND MODULATOR MEANS CONNECTED WITHE SAID GENERATOR MEANS AND WITH SAID SECOND INPUT MEANS FOR MODULATING SAID SECOND ANALOG VOLTAGE WITH SAID SECOND RECTANGULAR VOLTAGE; ADDING STAGE MEANS CONNECTED WITH BOTH SAID MODULATOR MEANS FOR ADDING THE MODULATED OUTPUT VOLTAGES THEREOF AND FOR FURNISHING A COMBINED OUTPUT VOLTAGE REPRESENTING THE SUM OF SAID TWO MODULATED OUTPUT VOLTAGES; MULTIPLYING MEANS CONNECTED WITH THE OUTPUT OF SAID ADDING STAGE MEANS FOR CHANGING THE VALUE OF SAID COMBINED OUTPUT VOLTAGE; AND DEMODULATOR MEANS CONNECTED WITH THE OUTPUT OF SAID MULTIPLYING MEANS FOR DEMODULATING SAID COMBINED OUTPUT VOLTAGE AS CHANGED BY SAID MULTIPLYING MEANS, SADI DEMODULATING MEANS BEING CONNECTED WITH SAID GENERATOR MEANS FOR BEING SYNCHRONIZED BY SAID FIRST AND SECOND RECTANGULAR ALTERNATING VOLTAGES IN SUCH A MANNER THAT SAID DEMODULATOR MEANS FOR DELIVER A FIRST AND SECOND FINAL OUTPUT VOLTAGE CORRESPONDING, RESPECTIVELY, TO SAID FIRST AND SECOND ANALOG VOLTAGE, BOTH SAID ANALOG VOLTAGES APPEARING IN SAID FINAL OUTPUT VOLTAGES AS BEING CHANGED IDENTICALLY IN ACCORDANCE WITH THE CHANGE APPLIED TO SAID COMBINED OUTPUT VOLTAGE BY SAID MULTIPLYING MEANS. 